Skin cells

Sahcyhc acid USP, EP, and other pharmacopeia grades are used medically as antiseptic, disinfectant, antifungal, and keratolytic agents. Sahcyhc acid is formulated in lotion or ointment formulations for the treatment of dandmff, eczema, psoriasis, and various parasitic skin diseases. Because the keratolytic property of this aromatic acid has use in the safe removal of dead skin cells from the surface of healthy skin, the acid is used in concentrated sahcyhc acid solutions or suspensions to remove warts and corns. In more dilute form, sahcyhc acid preparations have found use in dandmff and eczema treatment. Sahcyhc acid has been considered and found effective by the Advisory Committees to the FDA in various over-the-counter (OTC) dmg regulated uses. Among these are acne products, dermatitis, dry skin, dandmff and psoriasis products, and foot care products (24). 

Diugs with metabolic interactions that can enhance the half-life of active compounds. An example of this regimen is the interaction between azole- and vitamin D-deiivatives that inhibit the metabolism of retinoids in skin cells leading to increased intracellular amounts of active RA-isomers. Further study and the identification of novel interactions of this type ofdtug interaction is of great clinical interest since they may decrease the dose of retinoids required for efficacy thereby also reducing the risk of side effects of the retinoids. 

Griseofulvin (Grisactin) exerts its effect by being deposited in keratin precursor cells, which are then gradually lost (due to the constant shedding of top skin cells), and replaced by new, noninfected cells. The mode of action of flucytosine (Ancobon) is not clearly understood. Clotrimazole (Lotrimin, Mycelex) binds with phospholipids in the fungal cell membrane,... 

Like salicylic acid and resorcinol, it causes dead skin cells to slough off. 

Acne is caused when skin cells shed too quickly in hair... 

Benzoyl peroxide can help remove dead skin cells, which in turn prevents the pores from clogging up. It also kills the Propionibac-terium acnes bacterium that causes acne. It has anti-inflammatory effects and reduces oxygen free radicals and fatty acids on the skin. 

Salicylic acid is used to treat acne, warts, dandruff, psoriasis, and similar conditions. In the treatment of acne, it slows the shedding of skin cells in hair follicles, so they do not clog the pores and cause pimples. It also has a keratolytic effect—it causes dead skin cells to slough off— which removes the top layer of skin and clears existing pore clogs. 

The tamarind seed XG exerts several biological activities, such as marked inhibitory effect on the binding of BK virus to cells [299] and immunomodulatory effects [300]. Recently, it was reported [301] that XG affects the proliferation of cytokines in various skin-cell lines (Fig. 14) such as HaCaT cells (im-... 

Fabiato, A. Fabiato, F. (1978). Effects of pH on the myofilaments and the sarcoplasmic reticulum of skinned cells from cardiac and skeletal muscle. J. Physiol. 276,233-255. 

Keratinocyte proliferation is central to the clinical presentation of psoriasis. Keratinocytes are skin cells producing keratin which act as a skin barrier. Increased keratinocyte cell turnover (hyperkeratosis) results in the characteristic thick scaly skin lesions seen in patients with psoriasis.10,11 Hyperkeratosis results from immune derangements. 

Activated T cells begin releasing cytokines including interleukin-2 (IL-2), interferon-y, (IFN-y), tumor necrosis factor (TNF-a), and others.4,13 Cytokine activity leads to a rapid proliferation and turnover of skin cells, triggering the inflammatory process and the development of psoriatic skin lesions.4,13,14 TNF-a may have a role in disease severity it upregulates endothelial and keratinocyte expression of ICAM-1,... 

Keratinocyte The epidermal cell that synthesizes keratin, making up 95% of all epidermal cells commonly called skin cells. ... 

In both worm and fly, the Ras protein acts as a switch that determine cell fate. In C. elegans, the activation of Ras determines the formation of vulval as opposed to hypodermal (skin) cells (for sequence of events, see Table 8.4). In Drosophila photoreceptors, the activation of Ras determines the development of R7 as a neuronal as opposed to a cone cell. In both cases, Ras proteins operate downstream of receptor tyrosine kinases that are activated by cell-cell interactions. 

UV filters are currently considered as emerging environmental contaminants of increasing concern since most of the commonly used are known to cause endocrine disrupting effects in both aquatic and terrestrial organisms as well as in human skin cells [4]. These compounds bioaccumulate in fish at similar levels to polychlorinated biphenyls (PCBs) and DDT [5, 6]. 

Scientists have also since demonstrated that DNA (coated on microscopic gold beads) propelled into the epidermis of test animals with a gene gun , is expressed in the animal s skin cells. Furthermore, the introduction in this fashion of DNA coding for human influenza viral antigens... 

It is possible to identify various factors that confer on chemicals the ability to induce skin sensitization and allergic contact dermatitis. These include the capacity to gain access to the viable epidermis across the stratum corneum, to associate stably with host proteins, to provoke a certain degree of proinflammatory cytokine production by skin cells, and to be recognized by specific T lymphocytes. The effectiveness with which these requirements are met, and possibly other properties of the chemical that influence the vigor of induced immune responses, together with the extent of exposure, will dictate the degree to which sensitization is achieved. 

Radionuclides that do not emit beta particles likely emit alpha particles. An alpha particle is, in effect, a helium atom (two protons and two neutrons) ejected from an unstable nucleus. An alpha particle can only travel a few inches in air and cannot penetrate the outer layers of dead skin cells. Therefore, alpha particles are not external hazards and produce tissue damage only if alpha-emitting radionuclides are ingested, inhaled, or injected. 

Dust from animal houses consists mainly of organic matter (23). The preferred technique for investigating both the material composition of the dust and feed stuff is the WEENDER Analysis Technique (24). Table II shows the composition of dust from pig and hen houses compared to the feed fed. The differences in the protein content between dust and feed support the opinion that an important part of the dust originates from feathers, hairs, and skin cells of the animals. 

Mechanisms involved in UV-B-induced immune tolerance are multiple. UV-B irradiation strongly affects the viability and function of skin DCs [6]. UV-B irradiation causes DNA damage and apoptosis in LCs, while promoting their migration to regional lymph nodes [7]. This effect is paralleled by the reduced expression of MHC and costimulatory molecules, which results in an impaired antigen presenting capability. The release of IL-10 by resident skin cells, ker-atinocytes and mast cells, also contributes to dampen DC function [8, 9]. Thus, upon UV-B irradiation, immature or partially mature DCs,... 

Eimmel, S., et al.. Development of efficient transient transfection systems for introducing antisense oligonucleotides into human epithelial skin cells. Norm. Res., 54, 306-11, 2000. 

Like living organisms themselves, cells come in a remarkable variety of flavors. Brown has described what might be a human cell with elaborate internal structure. However, there is no such a thing as a typical cell. Afunctional liver cell, a hepatocyte, is quite distinct from a nerve cell, a neuron, that, in turn, is not much like a cell of the retina of the eye. Skin cells, pancreatic cells, kidney cells, cells of the testis and ovary, red blood cells, bone cells, and on and on, are all structurally, functionally, and metabolically distinct. Indeed, there are several types of cells in the skin, pancreas, kidney, testis, ovary, and bone. Then there are the cells of bacteria and other microorganisms that have no nucleus or other membrane-limited organelles very different. Diversity abounds. 

Epidermal growth factor EGE saUvary glands intestine cells of epidermal origin (e.g. skin cells) ... 

Chlorinated swimming pool exposures have also been Unked with respiratory effects, including asthma [140, 150-152]. Trichloramine, which is formed by the reaction of chlorine with urea (from sweat and urine), has been suspected in these cases of asthma. In addition to sweat and urine, pool waters also contain other DBF precursors, such as skin cells, hair, and lotions/sunscreens. 

Salicylic acid is a keratolytic agent that removes layers of cornified skin cells. Treatment for corns, calluses and warts involves the application of salicylic acid at a concentration of 1 1-50%. Salicylic acid is contraindicated in allergic patients and its use should be avoided in diabetic patients. 

Most and Bruckner (1936) found human tracks to be complex. A track contains a human species odor and an individual odor, both extruded through boots, but also the odors of crushed plants, disturbed soil, and leather or other shoe material. Dogs still tracked correctly after removal of one or several of these components. To separate the track components, the authors built a chair lift and a track wheel (Fig. 13.5). The rim of the metal wheel (approximately 2m in diameter) carried raised replicas of shoes at stride intervals. Pulled over the terrain, the wheel makes a track of crushed plants and disturbed soil without human scent. The lift consists of a chair suspended on a steel cable about 1.5 m above the ground. Although a person riding this chair leaves no foot imprints or disturbed soil, he/she still sheds odorous rafts of skin cells. A trained dog uses one or the other of these track components, as terrain and surface change. 

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